Fix broken next test:

Now after ran the test MM_PORT of test case for change of port the
enviroment variable is deleted.

Author: roramirez

Diff for: tests/e2e/port_config.js

@@ -36,6 +36,10 @@ describe("port directive configuration", function () {
 			// Set config sample for use in this test
 			process.env.MM_CONFIG_FILE = "tests/configs/port_8090.js";
 		});
+
+		after(function(){
+			delete process.env.MM_PORT;
+		});
 		it("should return 200", function (done) {
 			request.get("http://localhost:8100", function (err, res, body) {
 				expect(res.statusCode).to.equal(200);